nyc: NYC output is empty

I have been trying for hours to find the problem here, but I can’t, I tried many things, this is my test file (unit-test.js) inside projectRoot/test

var should = require('should');


var arr = [1, 2, 3];
function ap(ar) {
  a = ar;
  var L = a.length;
  if (L > 1) {
    a[L] = 4;
  }
  console.log(a);
  return a;
}

describe('#indexOf()', function () {
  it('should return -1 when the value is not present', function () {
    if (arr.length > 1) {
      should.equal(ap(arr)[3], 4);
      //should.equal(arr[2],3);
    }
  });
});

And this is my package.json:

{
  "name": "jsonave-test",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "lint": "eslint .",
   "test": " mocha test/unit-test.js --check-leaks --recursive --exit",
    "cover": "nyc npm test"
  },
  "author": "",
  "license": "ISC",
  "dependencies": {
    "http": "0.0.0",
    "jsonapter": "^2.0.3",
    "jsonave": "0.0.3",
    "moment": "^2.21.0",
    "nock": "^9.2.3",
    "should": "^13.2.1"
  },
  "devDependencies": {
    "eslint": "^4.19.1",
    "nyc": "^11.7.1"
  }
}

when i run , the output shows coverage all 0% and no file name is mentioned, as shown below

$ npm run cover

> jsonave-test@1.0.0 cover C:\Users\h\WebstormProjects\jsonave-test
> nyc mocha



  #indexOf()
[ 1, 2, 3, 4 ]
    √ should return -1 when the value is not present


  1 passing (0ms)

----------|----------|----------|----------|----------|-------------------|
File      |  % Stmts | % Branch |  % Funcs |  % Lines | Uncovered Line #s |
----------|----------|----------|----------|----------|-------------------|
All files |        0 |        0 |        0 |        0 |                   |
----------|----------|----------|----------|----------|-------------------|

About this issue

  • Original URL
  • State: closed
  • Created 6 years ago
  • Reactions: 34
  • Comments: 36 (9 by maintainers)

Most upvoted comments

The problem is, Mocha is not exiting after its execution. So coverage report is unable to print as the execution is hold by mocha. In Script of package.json mention --exit after mocha. EX- nyc --reporter=html --reporter=text mocha --exit

+38
sibajeeray on Jul 4, 2018

Maybe nyc doesn’t provide coverage inside the test files by default?

OK, makes sense although I had the same empty results even when I tested separate files.

I figured out my issue. I discovered a node_modules/.cache directory - deleting this made my coverage report work again. The previous committer had set the instrument: false flag in the nyc config. I noticed this and suspected it could be causing the empty results issue so deleted the flag but nyc still produced empty results, hence my confusion (I didn’t know about the cache).

+17
75lb on Jan 2, 2019

I’m really confused by this because all I did to get your example repo working was remove .nycrc

+5
JaKXz on May 4, 2018

@75lb I added a second file to your repro, I get coverage when I do that:

lib.js:

module.exports = { inc: x => x + 1 };

test.js:

const { inc } = require('./lib');
it('1', () => inc('1'))

Result:

$ npx nyc mocha test.js


  ✓ 1

  1 passing (6ms)

----------|----------|----------|----------|----------|-------------------|
File      |  % Stmts | % Branch |  % Funcs |  % Lines | Uncovered Line #s |
----------|----------|----------|----------|----------|-------------------|
All files |      100 |      100 |      100 |      100 |                   |
 lib.js   |      100 |      100 |      100 |      100 |                   |
----------|----------|----------|----------|----------|-------------------|

Maybe nyc doesn’t provide coverage inside the test files by default?

+4
quentinvernot on Jan 2, 2019

I have the same issue, reproduced on macOS High Sierra using node v6.14.4 and v11.4.0.

In an empty directory, install the deps.

$ npm i mocha nyc
$ npm ls --depth 0
broken-nyc@1.0.0 /Users/llobrook/Documents/tmp/broken-nyc
├── mocha@5.2.0
└── nyc@13.1.0

Create this file test.js:

it('one', function () {
  return 'one'
})

it('two', function () {
  return 'two'
})

Run mocha with nyc.

$ npx nyc mocha test.js


  ✓ one
  ✓ two

  2 passing (8ms)

----------|----------|----------|----------|----------|-------------------|
File      |  % Stmts | % Branch |  % Funcs |  % Lines | Uncovered Line #s |
----------|----------|----------|----------|----------|-------------------|
All files |        0 |        0 |        0 |        0 |                   |
----------|----------|----------|----------|----------|-------------------|

As you can see, the report is empty. Any ideas?

+4
75lb on Jan 2, 2019

there are a variety of reasons why coverage might be blank, and this thread seems to not be related to one specific cause. I’m closing this issue, but folks should feel free to open issues more specific to the problems they’re bumping into; ideally with a minimal reproduction in a repo.

+3
bcoe on Mar 12, 2019

The --exit option did not work for me. Is there any alternate fixes for this

In my case the tests are within the src folder and i’m running nyc command like: nyc mocha --recursive ./src.

The tests are passing but the coverage report is empty! Screenshot 2023-04-25 at 1 59 35 pm

+2
sayo96 on Apr 25, 2023

The problem is, Mocha is not exiting after its execution. So coverage report is unable to print as the execution is hold by mocha. In Script of package.json mention --exit after mocha. EX- nyc --reporter=html --reporter=text mocha --exit

Thank you. This worked like a charm.

+2
arjunpanicker on Apr 24, 2019

We should add to the troubleshooting steps to add cache: false somewhere in your nyc config when trying to reproduce. cc @bcoe [where do you think is best, the Issue template?]

Is everyone in this thread satisfied enough to close this issue? Perhaps a PR for 👆? 😃

+2
JaKXz on Jan 3, 2019

Hi had the same issue. mocha works correctly but nyc output and empty report.

"scripts": {
    "test": "mocha ./dist/utest/test.js --exit",
    "coverage": "nyc npm test",
  },  
  "nyc": {
    "include": [
      "dist/**/*.js"
    ],
    "reporter": [
      "text-summary",
      "html",
      "cobertura"
    ],
    "sourceMap": true,
    "instrument": true
}

=============================== Coverage summary ===============================
Statements   : Unknown% ( 0/0 )
Branches     : Unknown% ( 0/0 )
Functions    : Unknown% ( 0/0 )
Lines        : Unknown% ( 0/0 )
================================================================================
+1
diiiego83 on May 9, 2019

@Antonius-S feel free to open an issue 👍 just want to make sure we’re very specific about how to reproduce; these catch all issues almost never get solved, because there are multiple causes of empty coverage.

+1
bcoe on Mar 13, 2019

The same issue. Reproduced with stub.js from this post and nyc installed globally. In my case issue seems to happen only with global mocha:

D:\Projects\nyc-test>nyc node_modules\.bin\mocha


  √ should have tests

  1 passing (39ms)

----------|----------|----------|----------|----------|-------------------|
File      |  % Stmts | % Branch |  % Funcs |  % Lines | Uncovered Line #s |
----------|----------|----------|----------|----------|-------------------|
All files |      100 |      100 |      100 |      100 |                   |
 stub.js  |      100 |      100 |      100 |      100 |                   |
----------|----------|----------|----------|----------|-------------------|

D:\Projects\nyc-test>nyc mocha


  √ should have tests

  1 passing (39ms)

----------|----------|----------|----------|----------|-------------------|
File      |  % Stmts | % Branch |  % Funcs |  % Lines | Uncovered Line #s |
----------|----------|----------|----------|----------|-------------------|
All files |        0 |        0 |        0 |        0 |                   |
----------|----------|----------|----------|----------|-------------------|

NB: Curiously, the presence of option “all” either in arguments or in .nycrc file seems to change some things a bit:

----------|----------|----------|----------|----------|-------------------|
File      |  % Stmts | % Branch |  % Funcs |  % Lines | Uncovered Line #s |
----------|----------|----------|----------|----------|-------------------|
All files |        0 |      100 |      100 |        0 |                   |
 stub.js  |        0 |      100 |      100 |        0 |                 2 |
----------|----------|----------|----------|----------|-------------------|

though coverage info still weird. lcov.info when a call is correct (local mocha):

TN:
SF:D:\Projects\nyc-test\stub.js
FNF:0
FNH:0
DA:2,1
LF:1
LH:1
BRF:0
BRH:0
end_of_record

lcov.info for half-working call (global mocha & “all” option):

TN:
SF:D:\Projects\nyc-test\stub.js
FNF:0
FNH:0
DA:2,0
LF:1
LH:0
BRF:0
BRH:0
end_of_record
+1
Antonius-S on Feb 6, 2019

I have a similar problem where I’m not able to view any tests in the coverage summary. So far, I have:

test:vscode-integration": "node ../../scripts/run-vscode-integration-tests-with-top-level-extensions --reporter mocha-multi-reporters --reporter-options configFile=../../config/mochaConfig.json

the flags I have specified are:

  "nyc": {
    "reporter": ["text-summary", "lcov"],
    "temp-directory": "./coverage/.nyc_output",
    "all": true,
    "exclude": "typings",
    "extension": [".ts"],
    "sourceMap": true,
    "instrument": true,
    "include": ["src/**/*.ts", "src/**/*.tsx"]
  }

in the actual test script run-vscode-integration-tests-with-top-level-extensions I have:

shell.exec(
  `cross-env CODE_VERSION='1.30.0' ./node_modules/.bin/nyc cross-env CODE_EXTENSIONS_PATH='${path.join(
    __dirname,
    '..',
    'packages'
  )}' CODE_TESTS_WORKSPACE='${path.join(
    __dirname,
    '..',
    'packages',
    'system-tests',
    'assets',
    'sfdx-simple'
  )}' CODE_TESTS_PATH='${path.join(
    cwd,
    'out',
    'test',
    'vscode-integration'
  )}' node ./node_modules/vscode/bin/test ./node_modules/.bin/_mocha --exit`
);

and my output is

**lists all the tests here**
15 passing (57ms) 
Tests ended with 0 failure(s)
Existing test process, code should be 0
Tests exited with code: 0
=============================== Coverage summary ===============================
Statements: 0% ( 0/9 )
Branches  : 0% ( 0/7 )
Functions : 0% ( 0/1 )
Lines        : 0% ( 0/9 )
================================================================================

It looks like it’s running all the tests using the node test script I provided and mocha is being invoked internally through the vscode ‘testrunner’, so I’m confused as to what’s going on. Additionally, I do see files generated in the .nyc_output folder but the files are empty, and the lcov.info files have half data as well, so I’m assuming they aren’t writing correctly. I’m running these tests through vscode with typescript. Any help would be appreciated, thanks!

+1
AnanyaJha on Feb 8, 2019

I have not worked on that NYC since opening this issue, for those who still have their projects running, if @sibajeeray answer solves the issue, feel free to close it, else I will try something on it in the next couple of days.

+1
hayderma on Jul 4, 2018

I’m really confused by this because all I did to get your example repo working was remove .nycrc

So is that a bug in how nyc is processing the config file?

+1
redonkulus on May 4, 2018
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